Three-Level Optical Stark Effect of Excitons in GaAs Cylindrical Quantum Wires

This study looks at the three-level optical Stark effect of excitons in GaAs cylindrical quantum wires, utilizing the renormalized wave function theory. By applying the three-level model consisting of the first two electron levels connected via a powerful pump laser and the first hole level, we observe the appearance of the excitonic optical Stark effect through the appearance of two separated peaks in the exciton absorption spectra. In addition, the strong impact of the pump laser detuning and the wire radius on the optical Stark effect are also put under thorough examination. Finally, a brief guidance for experimental verification is also suggested.

The role of the VZn–NO–H complex in the p-type conductivity in ZnO

With the help of first-principles calculations, we investigate the VZn–NO–H acceptor complex in ZnO. We find that H plays an important role, because it lowers the formation energy of the complex with respect to VZn–NO, a complex known to exhibit p-type behavior. However, this additional H atom also occupies the hole level of VZn–NO making the VZn–NO–H complex a deep acceptor.

The Sinusoidal Buckling Mechanical Analysis for the Coiled Tubing Based on Energy Method

Columns are prone to sinusoidal buckling and repeated instability on the effect of drilling pressure and fluid pressure during drilling operation. The resulted large area of random contact to borehole wall would affect the drilling efficiency. It made the backreaming and loading hard and the drilling pressure low. Using energy method, taking flexural deformation energy and external potential energy of strings, hole section (slant hole, bending hole, level hole) and annular clearance etc. into consideration, derived the counting function of force that sinusoidal buckling occurred on coiled tubing when it contact with the wellbore, establishing the mechanical analysis method of calculating for sinusoidal buckling of slim lined construction roof bolt and string borehole. It proves an effective method for the applying of coiled tubing drilling pressure and the optimization of process parameters.

Future Antarctic ozone recovery rates in September–December predicted by CCMVal-2 model simulations

Chemistry-climate model validation phase 2 (CCMVal-2) model simulations are used to analyze Antarctic ozone recovery rates in 2000–2100 during local spring and early summer, both vertically integrated and at several pressure levels in the lower stratosphere. Multi-model median trends of monthly zonal mean total ozone column (TOC), ozone volume mixing ratio (VMR), wind speed and temperature poleward of 60° S are investigated. Median values are used to account for large variability in models, and the associated uncertainty is calculated using a bootstrapping technique. According to the selected ten CCMVal-2 models, Antarctic TOC will return to its pre-ozone hole level, taken as an average of 1970–1979 values, between 2065 and 2075 in September–November, and around 2050 in December. In 2000–2020, an increase in TOC is much smaller than in later years, and this is especially evident for December. Although the December TOC recovers to its pre-ozone hole levels earlier compared to all spring months (as the December ozone depletion was much lower), the rate of December TOC increase, is slower than that for all spring months. Projected trends in ozone VMR, temperature and winds at several pressure levels are analyzed in order to attribute the projected rate of December TOC recovery, as well as to investigate future changes in the Antarctic atmosphere in general, including some aspects of the polar vortex breakup.

ELECTRON AND HOLE EFFECTIVE g FACTORS IN InAs/GaSb QUANTUM WELLS

We investigate the Landau level structures and the electron and hole effective g factors in InAs / GaSb quantum wells under electric and quantizing magnetic fields perpendicular to interfaces. In these structures, the lowest electron level in InAs can be below the highest heavy-hole level in GaSb at zero magnetic field B. Thus the electron and hole levels anticross with the increasing magnetic field and the strong dependence of the Landau level structures as well as g factors on B is obtained. We have found that the voltage across the structure and the lattice-mismatched strain also produce the essential changes in the Landau level structures as well as the electron and hole g factors.

Impact of Boron and Gallium on Defects Production in Silicon

ABSTRACTWe report the results of comparison of radiation-induced defects (1 MeV electrons) in n+-p-p+ Si diodes doped with gallium or boron ranging in concentration from 8 × 1014 to 5 × 1016 cm-3, together with the impact of oxygen on radiation –induced defects. Present results provide evidence for new defects states in addition to those previously reported in gallium- and boron-doped Si. The combined boron and gallium data provide enough information to gain valuable insight into the role of the dopants on radiation-induced defects in Si. The interesting new future of our results is that the gallium appears to strongly suppress the radiation induced defect, especially hole level EV+0.36 eV, which is thought to act as a recombination center. Similarly the dominant electron level at EC-0.18 eV in B-doped Si (which act as a donor) has not been observed in Ga-doped CZ-grown Si.